Car-lighting system.



Patented Apr. 9, 1918.

W2 TNESSES J'NYEJVTUFL Hz-s ATTURNEX To all whom it'may concern.-

- circuits. It is neither necessary nor possible UN TE STATES PATENT OFFICE.

JOHN r. rm rLE, or SGHENECTADY, NEW YORK, AssIeNoR 'IO GENERAL ELECTRIC COMPANY, A CORPORATION or NEW YORK.

can-melamine SYSTEM.

Be it known that I, ,JOHN F. TRITLE, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State. of New York, have invented certain new and useful Improvements in Car-Lighting Systems, of which the following is a specification.

My invention relates to car lighting systems and more especially to devices for preventing a dimming or flickering of the lamps, due to excessive variations in voltage 1n the source of supply.

. Where electrlc ty s used as a motive power for vehicles, it is customary to use; the same source of power which supplies the traction motors to also supply the lighting in such power circuits'to maintain a constant potential because-of the sudden and large variations'in load. .The consequence is that there is a constant dinnning of the lights. Then, too, in those installations where the power is taken from a third rail this rail is broken at intervals, as when crossing anothersystem. These gaps inthe third rail are of such an extent that during aninterval of two or three seconds no power.

is supplied to the train, 7 and during this interval the lights will'go out. This flickering and dimming isa source of great an noyance to the occupants of the car. The object'of my invention is to provlde a device to be used in connection with a car lighting circuit where the same 1s connected tothe main source of supply" which wlll neutralizeor avoid the dimming and flicker ing referred to above. My device preferably consists of a compound wound dynamo electric machine whichis connected to the llght- 'ing circuit andnormally floats as a free run- .ning motor on the mainsource of supply. A

' suitable relay switch is provided which, upon a failure of the supply current, automatically disconnects this machine from the source of supply so'thatit pumps back as a generatorto feed the lighting. circuit so long as its momentum keeps it running. To in crease this efi'ect,I provide a fly-wheel upon .the machine which stores up kmet1c energy and gives it out as required.

Another object of my invention is to so arrange my device. that the series and shunt fields will act in conjunctlon whether the Specification of Letters Patent.

Patented Apr. 9, 1918.

Application filed December 18, 1913. Serial No. 807,448.

machine'isj'running as a motor or as a enerator.. By th1s arrangement I-am ena led to obtain the benefits of the characteristics of a compound generator and an accumula- A further object of myinvention is to arrange my 'machineso that the series field thereof is automatically shunted by a resistance when it runs as a motor and this shunt removed when it runs as a" generator. By a such an arrangement the speed of the machine is made as high as is consistent with stability when running as a motor and there by it is enabled to store up a large amount of kinetic energy for use when the power supply fails.

A further object of my invention is to provide means for automatically opening the circuit between the traction motors and my dynamo electric machine so that this machine can pump back only momentarily through thetraction' motors and will not try to supply power for running the car. If no such device is Provided mymachine would be heavily overloaded'and perhaps seriously injured as well as failing in its work of sustaining the lights.

The arrangement .which I have used will be more ciearly understood from an inspection of the accompanying drawing in which Figure 1 is a diagrammatic view showing the circuits and connections used. Fi s. 2

and 3 are dia ramsshowing the resu ting connections w en the relay'switch used is closed and open. respectively.

At 1 l have indicated a third rail, such as is commonly used, in which are found gaps 2-, such as would 700611? where the system crosses another system. Contacting with this third rail is the ordinary shoe or trolley 3 through which power is supplied to the traction motor circuit 4 and-to the arrangement which constitutes my invention. At 5 is indicated diagrammatically a dynamo electric machine, havlng one terminal connected to ground, and on the same shaft with which is a fly-wheel 6. This machine is provided with a shunt field winding 7 and v a series field winding 8-. The lightlng circuit which "is used for the vehicle is indicated at 9 as having one terminal connected to the in place.

ground. At 10 have shown diagrammatically a reverse current relay of common construction, wherein the shunt winding 11 is connected to the trolley at one terminal and at the other terminal is connected through a resistance 12 to ground. On the same relay there is supplied a series winding 13 which is so wound that it normally acts in conjunction with the shunt winding and serves to hold the core 14 in its raised position. To the relay armature are attached the pivoted switch arms 15 and 16, designed to contact with fixed points 17 and 18 respectively. Between the pivoted points of these contact arms I have bridged a preferably non-inductive resistance 20, the function of which will switch arm 16will contact with the fixed point 18 and serve a purpose to be later ex plained. Since power is now supplied to the dynamo electric machine 5, this machine wlll run asv a motor and will impart kinetic energy to the fly-wheel 6. It should be noted that the connections are so arranged that the series and shunt fields are aiding each other and that the resistance 20 is bridged across the series field 8 when the lower switch arm is closed. This resistance is so de signed that the excitation of the series field is reduced in order to speed up the motor as far as is consistent with stability. It should also be noted that without such a resistance between the switch arms, the series field would be short circuited and no flux induced thereby. This would be a disadvantage because it would necessitate the building up of the series fieldwhen the machine began its action'as a generator, and further the machine would not have a series characteristic for starting. The lamp circuit 9 is now connected in parallel to the dynamo electric machine running as a motor and receives power through the series winding of the relay, the switch arm 15, and the resistance 20 and the switch arm 16 in parallel with the series field 8. Suppose, now, that, the trolley 3 reaches a gap in the third rail and that consequently no power is being supplied to either the traction motors 'or the lamp circuit. Due to the momentum imparted to the fly-wheel 6, the dynamo electric machine will continue running in the' same direction and will momentarily pump back as a generator through-the series wind.

ing of the relay 10. Because of this reversal of current in the series winding, the two windings of the relay, will be opposed in their action and the core 14: will drop, opening the switch. Various results are accomplished thereby. First, the traction motor circuit is out off from the lighting circuit and the dynamo electric machine. My machine cannot therefore supply power to the traction motors andattempt to propel the vehicle. If it were possible for the machine to so supply power, it would be seriously overloaded, and the particular result which I seelr to accomplish would be impossible. Second, the shunt resistance across the series fieldis removed and it is put in series with the field. It will be noted that, whereas the upper terminal of the machine 5 was connected to the lower terminal of the series field winding 8 through the contacts 16 and 18, the opening of the switch leaves the "upper terminal of the machine connected to the upper terminal of the series field winding through the resistance 20. Thus, as will be clearly seen byreference to Figs. 2 and 3, the relative connection of said series field winding and said machine has been reversed. This results inlcausing a flow of current through the series field in the same direction as when the machine was running as a motor and in allowing the full current being generated to flow through said field,

thus giving 7 the maximum possible' compounding effect. 'Obviously,because of the momentary delay in .the demagnetization of the shunt coil 11 of the relay there will be an instant before the contacts 16 and-18 open when the machine will pump back to the trolley through the parallel circuit formed by the series field winding 8 -and the resist-' machine, a closed circuit is formed whereby.

the lamps will be supplied with energy; (See Fig. 3.) It should be noted that the compounding action of the two fields is continued while the machine acts as a generator because of the reversal of the connection relative of the series field winding and the brush terminals of the machine. and that because of this compounding action the voltage supplied by the machine will be sustained through a considerable drop in the speed thereof. I am thereby enabled to 1 L supply the lamp circuitwith approximately the desired voltage throughout the whole interval .when the trolley is crossing the gap in the third rail, I

From the above it will be seen that I I obtain' the objects desired, and that on a ifailure of power from the main source of w supply, my machine will act as a generator power is not necessary to cause the action I described above and thatshould there be a considerable decrea e in the voltage of the supply circuit, a similar action would take place. In other words, assoon as the counter-electromotive force generated in my machine exceeds the voltage impressed thereon from the outside source, it will cause current to How in the reverse direction with the result that the relay switch will drop out and the lamps be supplied from this machine instead of from the supply circuit.

This action will tend to avoid constant variations in the brilliancy of the lamps which is so often caused byv the greatvariations in voltage in the supply circuit. v I conceive that my device might be employed for other phrposes than that herein described and that various'modifications of the particular arrangement might be employed which would accomplish the same result. I, therefore, aim in theappended claims to cover all such modifications which come within the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States,

i. In combination across a source oi supply, a dynamo electric machine having a series field winding, a lamp circuit in parallel with the armature of said machine, and means responsive to a failure at the supplied current for connecting the lamp circuit and the series field in series in a shunt to the armature of said machine so that the flux in said field is in the same direction whether the machine runs as a motor or as a generator. v

2. The combination of a source of supply' with a closed circuit comprising an electrical load and a dynamo-electric ma-r chine with its series field winding, one side of said load being permanently connected to one side of said source of supply, a re- A movable connection, from the, conductor joiningsaid series field winding and said machine, .to the other side of said source of supply, and means responsive to the di-, rection ofthe flow of current between said source and said circuit for controlling said last named connection. v

- 3. In combination, a source of supply; translating devices energized from said means,

source, the said devices comprising an electrical load and an accumulatively compound wound dynamo-electric machine operating trolling the said devices, and connections whereby the said machine operates as an accumulatively compound wound generator supplying energy to the said load when the switch mechanism opens.

p 4:. In combination, a source of supply, an electric load and a dynamo-electric machine having-a shunt and a series field, a shunt for the series field winding, automatic means controlling the said shunt, and connections whereby'the said load and the said machine operating as an accumulatively compound wound motor are,,energ1zed from the source ator supplying energy. to said load, depending on the operation of the said automatic 5. In combination, a source of supply, translating devices energized from said source, the said devices comprising an electrical load and a dynamo-electric machine having a series field winding, and means responsive to the direction of current flow between said source and said machine for reversing the relative direction of thefield and armature currents of said machine and supplying the electrical load with energy from the said machine.

)6. The combination with a dynamo-electric machine having a series field winding,

as a motor, automatic switch mechanism conof supply or the said machine operates as v of an electrical load connected in series to the said field in a shunt circuit to tharmature of said machine, a source of supply,

and means energized from the source of supply for establishing a bridging connection-around the series field and connecting the said machine and load to the source or supply.

7. The combination with a dynamo sled.- tric machine having a series field windirig, or an electrical load connected in series with the said field in a shuntcircuit to the armature of said machine, a source of supply, and automatically operated electromagnetic switch mechanism for connecting the said lead and. machine to said source with the series field ofsaid machine shunted.

lit

8. The combination with a. dynamo-electric machine having a series field winding, of a resistance and an electrical load connected in series with the said field winding in a shunt circuit to the armature of said machine, a source of supply, and means energized from said source for connecting the .said machine to said source with the series field shunted by said resistance and the said lead connected in shunt tothe armature of said machine.

9. In combination, a source of supply, translating devices energized from said source, the said devices comprising a dynamo-electric machine having a series field winding and an electrical load connected in shunt to the armature of said ,machine, a shunt for the said field Winding, and ineans responsive to the direction of current flow between said source and said machine for controlling the said shunt, the direction of the flow of current through the said field winding, and the connection of said devices to said source. 1

10. The combination with a dynamo-electric machine having a series field winding, of an electrical load connected in series wlth 15- the said field in a shunt circuit to the armature of said machine, a source of supply,

electromagnetic switch mechanism having an operating coll energized from sa1d source for connecting the sald machlne to said source with the series field shunted and the electrical load connected in shunt to the armature of said machine, and'means energized responsively. to the flow of current from said machine to said source for opening the said switch mechanism.

11. In combination a" source of supply, translating devices energized from the said source; the said devices comprising a traction circuit, an electric load, and an accumulatively compound-Wound dynamo-electric machine, means responsive to the direction of current flow between said source and said machine for dis-connecting the said machine and the said load from the traction circuit and the source of supply, and connections whereby the said machine, dis-connected from said source, operates as an accumulative compound-wound generator supplying energy to said load.

.In witness whereof, I have hereunto set my hand this 17th day of December, 1913.

JOHN F. TRITLE.

Witnesses:

BENJAMIN B. HULL,

ORFORD. 

